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Biomedical subjects

J L Melnick

Publications and source records attributed to J L Melnick.

At least 163 records · Page 9Linked to original sources
PubMed1978

Cellular and humoral immunity in guinea pigs to two major polypeptides derived from hepatitis B surface antigen.

Guinea pigs immunized with hepatitis B surface antigen (HBsAg), types adw, adr and ayw, and with two major polypeptides derived from HBsAg/adw developed cell-mediated immunity as determined by the macrophage migration inhibition assay. Peritoneal exudate cells from animals immunized with a 22000- or a 25000-mol. wt. polypeptide derived from HBsAg/adw showed significant migration inhibition after challenge with either polypeptide or with purified HBsAg. Significant inhibition of macrophage migration was not observed when polypeptide-sensitized cells were challenged with normal human serum or with normal human liver extract. Similarly, a cell-mediated immune response was not observed in peritoneal exudate cells from animals sensitized to normal human serum or normal human liver extract which were challenged with either of the polypeptides. The humoral immune response to either of the polypeptides, as measured by radioimmunoassay, was substantially lower than that observed in animals immunized with intact particles. This apparent difference between cellular and humoral responses suggests that the macrophage migration assay is a sensitive indicator of the immunogenicity of the smaller mol. wt. HBsAg-derived polypeptides in guinea pigs.

Animals↗
PubMed1978

The fate of parental herpesvirus DNA after infection with normal and photoinactivated virions.

The fate of the 3H-dT-labelled parental DNA of normal and photoinactivated herpes simplex virus type 1 (KOS strain) was followed for 8 h after infection. The sedimentation coefficients of parental virus DNA from cells infected with normal virons increased and became associated with the replicative intermediates of HSV-1 DNA. When cultured in 5-bromodeoxyuridine-containing medium, the buoyant density of the normal parental virus DNA shifted to the hybrid region (containing heavy and light molecules) of the caesium chloride density gradient. The parental virus DNA of photoinactivated virions, however, degraded quickly and did not participate in progeny virus DNA replication.

Centrifugation, Density Gradient↗
PubMed1978

Concentration of enteroviruses from large volumes of tap water, treated sewage, and seawater.

Methods are described for the efficient concentration of an enterovirus from large volumes of tap water, sewage, and seawater. Virus in acidified water (pH 3.5) in the presence of aluminum chloride was adsorbed to a 10-inch (ca. 25.4 cm) fiberglass depth cartridge and a 10-inch pleated epoxy-fiberglass filter in a series at flow rates of up to 37.8 liters (10 gallons) per min. Adsorbed viruses were eluted from the filters with glycine buffer (pH 10.5 to 11.5), and the eluate was reconcentrated by using a combination of aluminum flocculation followed by hydroextraction. With this procedure, poliovirus in large volumes of tap water, seawater, and sewage could be concentrated with an average efficiency of 52, 53, and 50%, respectively. It was demonstrated that this method is capable of detecting surface solid-associated viruses originating from sewage treatment plants. No difference in virus recovery between laboratory batch studies and a set-up with acid-salt injection was found. This unified scheme for the concentration of viruses has many advantages over previously described systems. These include: high operating flow rates, low weight and small size, effectiveness with a variety of waters with widely varying qualities, and filters with a high resistance to clogging.

Enterovirus↗
PubMed1978

Concentration of poliovirus from tap water onto membrane filters with aluminum chloride at ambient pH levels.

A method is described for the concentration of an enterovirus from large volumes of tap water by addition of small amounts of aluminum chloride to enhance virus removal by membrane filters. Tap water treated with 2 X 10(-5) M aluminum chloride showed a slight decrease in pH (less than 0.5), a slight increase in turbidity, and enhanced removal of poliovirus by membrane filters. Virus was quantitatively recovered by treating the filters with a basic buffer, and this eluate was reconcentrated to a small volume by adsorption to aluminum hydroxide flocs. Using these procedures, virus from 1,000 liters of water was reduced to a final eluate of 20 to 80 ml with a mean recovery of 70%.

Adsorption↗
PubMed1978

Role of sediment in the persistence of enteroviruses in the estuarine environment.

The survival of four enteroviruses commonly found in sewage effluents was examined when the viruses were adsorped to marine sediments in estuarine water and compared with virus survival in estuarine water alone. Echovirus 1, coxsackieviruses B3 and A9, and poliovirus 1 survived longer when associated with marine sediment. When the estuarine water was polluted with secondarily treated sewage effluent, virus survived for prolonged periods in sediments, but not in the overlaying estuarine water.

Enterovirus↗
PubMed1978

Development of quantitative methods for the detection of enteroviruses in sewage sludges during activation and following land disposal.

The development and evaluation of methods for the quantitative recovery of enteroviruses from sewage sludge are reported. Activated sewage sludge solids were collected by centrifugation, and elution of the solid-associated virus was accomplished by mechanical agitation in glycine buffer at pH 11.0. Eluted viruses were concentrated either onto an aluminum hydroxide floc or by association with a floc which formed de novo upon adjustment of the glycine eluate to pH 3.5. Viruses which remained in the liquid phase after lowering the pH of glycine eluate were concentrated by adsorption to and elution from membrane filters. The method of choice included high pH glycine elution and subsequent low pH concentration; it yielded an efficiency of recovery from activated sludge of 80% for poliovirus type 1, 68% for echovirus type 7, and 75% for coxsackievirus B3. This method was used to study the survival of naturally occurring virus in sludge at a sewage treatment plant and after subsequent land disposal of the solids after aerobic digestion. Reduction of enterovirus titers per gram (dry weight) of solids were modest during sludge activation but increased to a rate of 2 log 10/week after land disposal.

Buffers↗
PubMed1978

A simple method for concentration of enteroviruses and rotaviruses from cell culture harvests using membrane filters.

Organic compounds in cell culture harvests known as membrane-coating components (MCC) prevent virus adsorption to membrane filters. Blending cell culture harvests with fluorocarbon removed the MCC and permitted adsorption of virus in acidified harvests to epoxy-fiberglass filters. Subsequent elution with high pH buffer resulted in recovery of greater than 90% of the virus with concentrations of up to 100-fold.

Enterovirus↗
PubMed1978

Coxsackievirus aggregates in muscle cells of a polymyositis patient.

Muscle biopsy specimens of a patient with polymyositis showed crystalline structures resembling picornavirus aggregates within muscle cells. The patient's serum reacted in an indirect immunofluorescence assay with autologous muscle cells. A strongly positive immunofluorescence staining was also noted when a section of muscle tissue was reacted with coxsackievirus A9 antiserum, and a weakly positive reaction was noted with coxsackievirus B2 antiserum. No staining was observed after treatment with antiserum to poliovirus type 1 or echovirus types 11 and 22.

Aged↗
PubMed1978

Association of cytomegalovirus (CMV) infection with cervical cancer: isolation of CMV from cell cultures derived from cervical biopsy.

Cytomegalovirus (CMV) was isolated from cell cultures derived from 2 of 10 cervical cancer biopsies from patients in an advanced stage of the disease. Five serial passages were necessary before extensive cytopathic changes characteristic of CMV infection appeared. All patients tested had complement-fixing antibodies to both isolates in higher titers than to the prototype AD169 strain. 6 of 8 patients tested also had herpesvirus type 2 antibodies.

Adult↗
PubMed1978

Human studies following models of tumorigenesis by DNA tumor viruses in animals.

The discovery of virus-specific messenger RNA in virus-induced animal tumors has led to the search for messenger RNA in human tumors that can be hybridized with the DNA of known oncogenic viruses. Attention has focused on the adenoviruses, which have produced cancer in laboratory animals and are widespread in man, and on three papovaviruses that have been isolated in human disease and which are oncogenic in hamsters. In other research, the association between human infection with herpesivurs type 2, which is likewise oncogenic in hamsters, and invasive carcinoma of the cervix is being examined. An experimental vaccine is being developed, and nonhuman primate models are being studied as part of this work. Epstein-Barr virus is still another suspected agent of human malignancies, specifically Burkitt's lymphoma and postnasal carcinoma. High prevalence of antigen to hepatitis B virus has been seen to correlate with high incidence of primary liver cell carcinoma, and studies are attempting to elucidate the relationship.

Adenoviruses, Human↗
PubMed1978

Advantages and disadvantages of killed and live poliomyelitis vaccines.

Decision-making on the use of poliomyelitis vaccines in the WHO Expanded Immunization Programme, and particularly in the developing nations, needs to be based on an understanding of the epidemiology of poliomyelitis in different parts of the globe. Even with two safe and effective kinds of poliomyelitis vaccine available, poliomyelitis has by no means been eradicated from the world. In developed countries that are considered well-vaccinated, certain sectors of the population may be inadequately protected against risk of infection by indigenous or imported wild polioviruses. In developing nations that are in transition toward an epidemic phase of poliomyelitis, wild polioviruses will continue to be a threat until thorough immunization is established and maintained. Killed-virus poliomyelitis vaccines have proved to be effective in certain countries that have used them exclusively; these are small countries with excellent public health systems, where coverage by the killed vaccine has been wide and frequent. Live vaccines, administered to hundreds of millions of persons during the past decade, have also been remarkably safe and effective. However, in certain warm-climate countries induction of antibodies in a satisfactorily high proportion of vaccinees has been difficult to accomplish. The advantages and disadvantages of each kind of poliomyelitis vaccine need to be weighed with respect to the particular setting in which a vaccine has been or will be used.

Child↗
PubMed1978

Viruses in water.

Attention is drawn in this paper to the increasing problem of viral contamination of water and shellfish, particularly since growing demands for available water resources by a rising world population and expanding industry will make the recycling of wastewater almost inevitable in the future. The problem of eliminating viruses pathogenic for man from water is considered in the light of present water treatment procedures, which are often inadequate for that purpose. Man may be exposed to waterborne viruses through the consumption of contaminated water, shellfish, or crops, as a result of recreational activities involving water, or from aerosols following the spraying of crops with liquid wastes. Physical and chemical methods of eliminating viruses from water are discussed.

Humans↗
PubMed1977

Viral hepatitis.

Explore the source record for details and available documents.

Hepatitis B Antigens↗
PubMed1977

Experimental carcinoma of liver in macaque monkeys exposed to diethylnitrosamine and hepatitis B virus.

The effects of treatments with diethylnitrosamine (DENA) and hepatitis B virus (HBV) on macaque monkeys were investigated by virus serology and by light and electron microscopy. The experimental groups comprised 43 newborn or juvenile cynomolgus and rhesus monkeys of both sexes. HBV neither had a carcinogenic effect nor increased the oncogenic effect of DENA. However, HBV given to juvenile primates before treatment with DENA resulted in subsequent gross and microscopic alterations consistent with mild hepatitis and postnecrotic cirrhosis; multifocal liver carcinoma apparently developed within these cirrhotic nodules. The pathologic findings in the experimental animals were strikingly similar to those observed in liver cancer patients.

Animals↗